Technical Abstract:
There are periods during pregnancy when sows may have a higher requirement for certain vitamins and minerals than that normally supplemented in their diet. Proteins transferring retinol and Fe to the developing pig fetus have been identified, whereas transport mechanisms for other vitamins and minerals have not yet been elucidated in the gravid pig. Although sow body ytissue can serve as a reservoir for many nutrients, it is not known if these reserves can supply adequate quantities of nutrients during critical fetal developmental periods. In some cases, there is inadequate placental transfer of some nutrients (e.g. vitamin E) even though the gestating animal is fed high dietary levels of the nutrient, requiring that colostrum and milk provide these nutrients to the pig postnatally. Sow body homeostasis maintains some nutrients at constant levels (e.g. Ca and P) in the fetus and milk supply resulting in bone demineralization in older sows. .Other nutrients are depleted from sow tissue reservoirs over several parities (e.g. Se) with lower quantities subsequently being provided in the milk for the nursing pig. Knowledge involving adequate vitamin and mineral nutrition to the female pig which will result in embryonic survival, improved conception rates, and optimum fetal and postnatal pig development can be considered in its infancy.